30 
Further it must be emphasized that our terms: mono-, bi- 
and tetrasporical are by no means identical with those of 
Courter’s. Deduction has lead us to distinguish ; | 
nine types of monosp. sacs, viz. A, Az, Ay, B, Bz, (BS), C, Cz, and D. 
five types of bispor. sacs, viz. AA, (AAS), BB, (BBz), and CC. 
_ (two types of trispor. sacs, viz. AAAz, and BBB). 
one type of a tetrasporic. sac, viz. AAAA. 
Coutter however, identifying megaspore-formation and chroma- 
tine-reduction, discerns three types only: 
monosporical sacs (including our types A and B) 
bisporical sacs (including our types C, AA and BB) 
tetrasporical sacs (including our types D, AAAA and CC). 
This distinction is not a theoretical question of nomenclature, 
but based on a real difference. Our 17 types are no fancies but 
plainly distinguishable forms. For instance Lilium, Peperomia 
and Gunnera are all three considered from Covrrsr’s point of 
view, to be of a tetrasporical nature and of the same megaspore- 
formation. In fact however the early stages of development are 
not the same, vacuolation following ‘the first division of the 
embryosac-mothercell in Lilium, the second division in Gunnera 
and the third division in Peperomia. Lilium therefore must be 
‘classified as belonging to type D, Gunnera as to type CC and 
Peperomia as to type AAAA (fig. 2, p. 22). 
Thirdly it is good to point out again, that actually wo lines 
of development are joined in fig. 4, viz. the omission of cell- 
wall-formation and the germinating of two or more megaspores. 
‘Of these two the first line is fully worked out; the other one 
however only inasfar as it coincides with the’ first one and thus 
influences the number of nuclei in the developing embryosac. 
As already stated above, we have left out of discussion the 
very many cases in which two or more normally formed me- 
geeporee (separated by cell walls) are seen fenghonhey 
Dcchghasn of the mnicronies group ae wile 
Normally the primary micropylar nucleus by two successive 
divisions gives rise to a group of four nuclei. Spindles in the 
second division are almost always showing “j° shape. The uppét 
